Inertia member for retarding breechblock movement in automatic firearms



Jan. 24, 1950 2,495,460

J. KoucK? INERTIA- MEMBER FOR RETARDING BREECHBLOCK MOVEMENT IN AUTOMATIC FIREARMS Filed Sept. 5, 1947 Patented Jan. 24;, 1950 Nr STATE DFFICE manna EMBER Fon RETARDING snEEcnsLocK MOVEMENT IN AUTO- MArIc FIREARMS Josef Koucky, Prague, Czechoslovakia, assigncr to Zbrojovka Brno, Narodni Pmlnik, Prague, Czechoslovakia, a corporation of Czechoslovakia Application September 5, 1947, Serial No. 772,242 In Germany December 11, 1942 Section 1, Public Law 690, August 8, 1946 Patent expires December 11, 1.962

3 Claims. (or. 42-46).

In a prior application for patent of the United States, Serial No. 300,195, filed October 19, 1938, now abandoned, I have described an unlocked breech mechanism adapted for use with such firearms which was provided with a retarding device in the form of a weighty body seated and freely movable on a rod extending between and connecting the two halves'oi the breech block which were spaced to allow the body to eiTect axial movements in either direction between and relative to these halves. On the pistol being fired, the powder gases acting on the breech block force it rearwards together with the movable body, but on the block being stopped by the recuperator spring, the movable body continuing on its rearward movement owing to its inertia will strike the rear half of the breech block and thereby retards the subsequent forward movement of the block, thus diminishing the rapidity of fire.

In the embodiment of the device shown and described in my prior application, the movable body had the form of a closed ring encircling the supporting rod on which it rode. Obviously, a removal of a body of closed annular cross-section from the rod for purposes of cleaning or repair or replacing it by a body of greater or lesser weight in order to change its retarding action, takes time and requires the use of tools, whereby the utility of the arm in warfare is lessened considerably.

It is an object of my present invention to so improve this breech mechanism as to enable the temporary removal or the replacement of the retarding body to be efiected without any appreciable loss of time and without the use of tools.

In the drawings afiixed to this specification and forming part thereof, two embodiments of this invention are illustrated diagrammatically by way of example.

In the drawings:

Fig. 1 is an axial section of that part of an automatic pistol or other firearm, in which the breech mechanism is housed and operated, this mechanism being shown as being constituted according to one form of this invention, the top of the breech case being broken away in part inorder to more clearly show the breech block.

Fig. 2 is a perspective view of the breech block proper, and

Fig. '3 is a similar view of the movable body, movably seated in the central gap of the block.

Fig. 4' is a perspective of another form of breech block, and

Fig. 5 is a similar view of the type of movable body adapted to be used together with it.

Referring to the drawings and first to Figs. 1-3, I is the breech case, 2 is the barrel, 3 is the breech case opening through which the cartridges enter the breech case and 4 is the opening through which the cartridge cases are ejected after firing. 5 is the breech block, here shown as a metal cylinder, the middle top portion of which is cut away by about one-third of its diameter and about two-fifths of its length, leaving the middle portion 6 as a bridge between the cylindrical ends. This bridge piece is formed with a longitudinal gap I. Into this gap extends the stem portion 8 of the movable body shown in Fig. 3, this portion having an oblong rectangular cross section and being topped by a vaulted head piece 9 which fits the cylindrical contour of the breech block, while the stem portion fills that part of the gap I in.

which it is supported by the head piece 9 whose plane bottom faces rest on the two halves of the bridge portion 6. The axial length of the cut away portion of the breech block is considerably greater than that of the movable body 8, 9 which is therefore at liberty to move freely in the direction towards one or the other end of the block. IE! is the firing pin housed in the forward portion and II is the recuperator rod fixed to the rear portion of the breech block and carrying the recuperator spring I2.

Obviously, the body 8, 9, being free to slide axially in the gap 1 of the breech block, will exert a similar inertia effect on the block as did the annular body described in my prior application for patent. In view of its being inserted loosely in the middle gap formed in the breech block, it can be withdrawn from the block with the greatest ease and without the use of tools.

The embodiment shown in Figs. 4-5 comprises a breech block formed of two cylindrical end sections I3, I4 and a middle bridge section I5 connecting same, this middle section having the form of a rather narrow four-sided prism with parallel sides fit to support a movable mass body l6 as shown in Fig. which may be described as a cylindrical section formed with an open prismatic groove extending from the bottom of the piece It up to near its top. This mass body, if placedon the middle section l5 of the block, is free to ride and slide thereon towards and away from either end section, and, under firing conditions, to exert on the block the inertia effect above described. Obviously, the body Hi can easily be lifted off the bridge section I5 without the use of tools.

In both embodiments here shown and described the movable body is so shaped as to be adapted to be extracted through the openings'provided in the breech block for the passage of cartridges and to fit exactly the outlines and fill up the crosssectional area of the breech block proper. It is, however, obvious that this is not a condition for the proper working of the device.

While the breech block proper has been shown as having the form of a cylinder fitting in a cylindrical boring of the breech case, it is to be understood that the outer contour of the breech block may be diiierent altogether, provided only that, the movable mass body be so shaped as to .be supported on the breech block for free sliding movement towards and away from contact faces provided near the ends of the block and at the same time to be readily removabl from its combination with the block without the use of any tools and without dismantling the block itself.

The side walls of the gap in-the first embodi- I wish it to be understood that I do not desire to be limited to the details of design and construction shown and described, for obvious modifications will occur to a person skilled in the art.

I claim:

1. A breech mechanism for automatic fire arms comprising in combination, a. breech case, a breech block arranged in said case for reciprocation under the action of forces arising when the arm is being fired, said block being composed of two relatively spaced end sections and a middle section of smaller cross-sectional area connecting said end sections, and a weighty body supported on said middle section for free sliding movement towards either end section and fitting between said end sections with a considerable clearance, said body interlocking with said middle'section'in open slot and key engagement for free insertion and removal at right angles to the breech block axis.

2.;The breech mechanism of claim 1, in which the middle section of the breech block is formed with a longitudinal gap or groove and the movable body with a stem extending between and into contact with the side walls of said gap or groove.

3.' The breech mechanism of claim 1, in which the movable body is formed with a substantially vertically extending groove opening towards the bottom of said body and straddling the middle section of the breech block. a

. JOSEF KOUCKY.

REFERENCES CITED Name Date Mertens June 23, 1908 Number 

